President Rodrigo Duterte said nthe government is still investigating what really took place that led to the withdrawal of Philippine ship in a standoff with the Chinese vessel in Scarborough Shoal in West Philippine Sea some eight years ago.

In the pre-recorded "Talk to the People" aired on Monday night, Duterte said part of the investigation was the role of former Foreign Affairs Secretary Albert del Rosario whom he threatened to pour with a cup of coffee as he debunked his allegation that Chinese officials had helped him won in the 2016 presidential polls.

"I want to coordinate or I just want to talk to some people in Washington be it from the Office of the President or State Department or Defense Department. We are still investigating it," he said.

"But you, Alberto, if I see that you have (role in the withdrawal of the Philippine ship), I will charge you," Duterte said, adding that this would be the first time that he would personally file a complaint against someone.

He noted that in his 23 years in public service, he never sued anybody for libel or for anything.

The President said he would go after Del Rosario and "if we're only at war, you're guilty of treason."

Duterte became irked by Del Rosario's earlier statement that high officials from China were bragging that they had been able to influence the 2016 Philippine elections so that the former Davao City mayor would become president.

Duterte denied the former DFA chief's allegation as he wondered how a foreign country could buy the more than 16 million Filipinos who had voted for him. He cited that he had won in the 2016 elections with a margin of over six million votes from his closest opponent.

"I wonder if you (Del Rosario) are a Filipino," he said, adding that he wants to personally meet with the former DFA official and pour a cup of coffee on his face.

"I will go to you. I won't bring a security. I will pour coffee on you," he said. Celerina Monte/DMS